The invention concerns an artificial lens for simulation of the human lens in the eye. Until now, in so-called "star operations [cataract removal]", the human lens has been removed and replaced with an artificial lens.
In this process, it is known to remove the existing human lens (i.e., the lens nucleus) in its entirety from the capsular sac. The lens consists of a lens nucleus, a lens cortex, and a lens capsule, which surrounds the lens.
The lens capsule must be removed at the beginning of the operation (preferably by means of capsular hexis).
At the end of such an operation, an artificial lens is inserted for reasons of optical rehabilitation.
Techniques are currently known for simulating such an operation on practice eyes. Here, as a rule, animal eyes, such as pig eyes, rabbit eyes, or even human eyes, are used to learn such a surgical technique for removal of the lens nucleus and the lens cortex.
In U.S. Pat. Nos. 4,865,551; 4,762,495; 4,865,552; and 4,762,496, simulation techniques have been disclosed whereby an artificial lens is disposed in a so-called "three-chamber system" to learn the aforementioned surgical technique.
Here, an artificial cornea is used with an artificial iris, which covers the artificial lens from above, and the operator opens the lens capsule through the artificial iris after opening the cornea in order to remove the artificial lens according to the prior art using common instruments. A known removal method is extraction using ultrasound (phacoemulsification).
The advantage of this separation method according to Maloney lies in that the training model can be used repeatedly under conditions which always remain the same, whereby only the artificial lens must be replaced.
However, a disadvantage of the known artificial lens is that it is only partly comparable with the human lens. According to the patents mentioned above, it comprises an alginate with the addition of plastic components, a fact which is associated with the disadvantage that lens removal cannot be realistically performed using the aforementioned phacoemulsification.
In phacoemulsification, the lens must be divided into various sections by the operator. These individual sections are then fragmented using ultrasound and aspirated. Because of the relatively unfavorable properties of the lens material used, with the Maloney lens it is possible only with difficulty to divide the lens into various sections comparable to the human operation. The sections cannot be separated; instead, they disintegrate and crumble.
The usual practice for this is to split the lens into a total of four parts. The subsequent phacoemulsification then results in the fact that the lens particles of the known Maloney lens block the aspiration system in the ultrasound hand tool used for the hose system.
According to another operation technique, the lens nucleus is removed as a whole from the capsular sac.
This second so-called extracapsular operation technique cannot be performed with the so-called Maloney system with the rigid three chamber system.
Consequently, the object of the invention is to improve a lens of the type mentioned above such that it has significantly better homogeneity and improved elasticity, and largely corresponds overall with the human lens in its mechanical properties.